This document discusses the three modes of heat transfer: conduction, convection, and radiation. Conduction involves the direct transfer of heat between objects in contact through molecular motion. Convection involves the transfer of heat by the circulation of fluids like air and water. Radiation involves the transfer of heat through electromagnetic waves and does not require a medium. Examples of each mode are provided, such as conduction through touching a hot stove, convection through boiling water, and radiation through heat from the sun.

1. MODES OFHEAT
HALEEMULLAH 1
Assignment
 Name: Haleemullah
 F/Name: Muhammad Shaiq
 Roll No: D-19-EE-04
 Subject: Heat And Mass
Transfer
 Submitted: Mr Aamir Raza

2. MODES OFHEAT
HALEEMULLAH 2
HEAT TRANSFER.
So Heat is the form of energy which is associated with the motion
of molecules or atoms. The heat transfer takes place from the
high-temperature body to low-temperature body.
Example:
When we cook food. Initially, we provide heat and after preparing
food we are trying to extract heat to eat the cooked food. So what
we do for, we are keeping to an open environment or near to fan.
So the temperature of the air is less than the temperature of
cooked food, it (temp) starts emitting to surrounding and this
process goes on till both come in the normal temperature.
The extreme or moderate or low heated object leaves the heat at
the room temperature. Now further it has been categorized in the
3 types which are:
Modes of Heat Treatment:
There is a total of 3 Modes of Heat transfer which is:
1. Conduction
2. Convection and
3. Radiation

3. MODES OFHEAT
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1. Conduction:
In Conduction, the heat or energy is transferred by a direct
contact like when any heated object you touch with your hand the
conduction process take place.
When we heat the Iron at one side the other side automatically
gets heated because the molecules present in it travels to another
side and heated that area too. So we can say Conduction is equal
to Direct contact
It is defined as the transfer of heat by means of molecular
agitation within a material without any motion of the material as a
whole.

4. MODES OFHEAT
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Example:
a) Touching a stove and being burned.
b) Ice cooling down your hand.
c) Boiling water by thrusting a red-hot piece of iron into it.
d) You can warm your back muscles with a heating pad.
e) After a car is turned on, the engine becomes hot.
f) The heat from a hot liquid makes the cup itself hot.
g) Hot food will heat a stoneware or porcelain plate for a time.
2. Convection:
In convection, the heat or energy is transferred by mass motion of
fluid which might be air or water when heated fluid is caused to
move away from the source of heat-carrying energy with it.
Example:
a) When the heat is provided to water at the bottom the pot is
heated, the water particles move faster, and they also move
farther apart. So now the heated water becomes less dense
and we know the less-dense fluid will float on top of a more
dense one. Now, the heated water rises in the pot. The
surrounding cooler water flows into its place. This flow
creates circular motion, known as convection.
b) Boiling Water. Convection comes into play while boiling
water.
c) Air-Conditioner.
d) Radiator.
e) Refrigerator.
f) Hot Air Balloon

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3. Radiation:
The Radiation is defined as Everybody emits radiation in the form of an
electromagnetic wave or rays or particles. In this process does not
require a medium to transfer the Thermal (Heat) energy.
Example:
a) In summer when you go in the field and for a time you stand
there you will feel heat up because of sun emits the heat and your
body skin receives. That is how the radiation process works.
b) Heat from a stove burner.
c) visible light from a candle.
d) alpha particles emitted from the radioactive decay of uranium.
e) microwaves from a microwave oven.
f) sound waves from your stereo.
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